Summary of Core B The Molecular Biology Core (Core B) will provide expert and efficient laboratory services to Project 1 (Saper), Project 2 (Scammell) and Project 4 (Chamberlin). The major duties of Core B are management and genotyping of mouse colonies and performing in situ hybridization histochemistry. Core B will also manage bacterial clones for in situ hybridization and viral vectors, and produce new/modified DNA construct as technology evolves. Core B is designed to optimize efficacy, accuracy and expertise. The Core will manage large, shared mouse colonies to ensure a reliable and efficient supply of accurately genotyped mice for each Project. The Core also will centralize the performance of complex molecular techniques such as in situ hybridization histochemistry and bacterial culture so researchers in the Projects can focus on the science instead of debugging techniques. Our years of experience with these methods maximizes the likelihood that the complicated molecular techniques proposed in this PPG will succeed.